INTRODUCTION: The World Health Organization (WHO) has focused on evaluating the relationship between disease and the environment. In that preventable, focuses on environmental risk factors. Maternal exposure during pregnancy to chemicals, drugs, alcohol, tobacco, radiation, and some infections, may increase the risk of
having a newborn affected by congenital anomalies. The problem at the time of data collection in conducting the research work is focused on the construction of the instruments to be used for this purpose, in order to gather valid and reliable information. Validity can´t be quantitatively expressed, it’s rather a question of judgment, usually using the Expert Judgment. OBJECTIV: To develop an instrument to evaluate maternal risk factors to environmental xenobiotics, which allows to analyze the association of these variables with the occurrence of cases of major congenital anomalies and obtain preliminary results. MATERIALS AND METHODS: A questionnaire was developed to collect personal, sociodemographic data, domestic exposure, direct and indirect work to chemical substances, behavioral habits, hygienic-dietary and health status in women. It was prepared based on available literature and instruments previously used by the Latin American Collaborative Study of Congenital Malformations (ECLAMC) and WHO. They were then put to the consideration of three international experts, and subsequently, they were tested through personal interviews with post-partum women from two public hospitals of reference in Santa Fe City, Argentina. Data was analyzed using the InfoStat software. RESULTS: 36 women between 15 to 42 years old, were surveyed. 38.9% (14/36) of them came from Santa Fe Capital, 19.4% (7/36) from localities near Santa Fe, and 41.7% (15/36) from the countryside of the province. 27.8% (10/36) lived less than 100m from a factory, workshop or industry and 13.8% (5/36) lived less than 100m from agricultural fields. Regarding education level, 16.6% only completed primary school, 44.4% didn´t have completed secondary education, and 30.5% have completed it. 75% (27/36) used some chemical to control insects at home. Although 38.9% (14/36) smoked before pregnancy, only 2.7% (1/36) keep doing it during pregnancy. However, 44.4% (16/36) were passive smokers both before and during pregnancy. 13.9% (5/36) had a miscarriage at least once in their lifetime, and 55.5% (20/36) and 61.1% (22/36) consumed iron and folic acid during pregnancy, respectively. DISCUSSION: the development of the instrument and its validation by three experts allowed its use in a pilot test with a representative sample of population. The adequacy of the questions to our reality and language, and the diversity of places of origin of the respondents, provided a diagnosis of the situation of the surveyed population. In this way, the developed instrument demonstrated its relevance for application in future epidemiological studies throughout the province of Santa Fe.